Corrugated board slitting machines



I July 2, 1957 1. K. SCHMIDT ETAL CORRUGATED BOARD SLITTING MACHINES 3 Sheets-Sheet 1 Filed March 9, 1955 July 2, 1957 L. K. SCHMIDT EI'AL CORRUGATED BOARD SLITTING MACHINES Filed March 9, 1955 5 Sheets-Sheet 2 United States Patent ice 2797751 7 PatentedJuly 2, 1957 proved type of knife or blade holder capable of individual adjustment both laterally upon its support and for indi- 2,797,751 vidual adjustment of the knives to determine the depth CORRUGATED BOARD SLIT TING MACHINES Louis K. Schmidt and Robert E. Schmidt, Elgin, 111., assignors to Elgin Corrugated Box Company, Incorporated, Eigin, 11]., a corporation of Illinois Application March 9, 1955, Serial No. 493,114

2 Claims. (Cl. 164-39) Our invention relates to corrugated board slitting machines.

Our invention relates more particularly to a novel machine for cutting or slitting a sheet of corrugated board in such manner that the unit may be folded to form a layer of a protective skeleton padding adapted to fit into a shipping container to protect an article during shipment.

In other machines of the type used for this purpose the knives for cutting the corrugated board are usually rotary and are rotated at the same speed as the speed of the corrugated board passing through-the machines. Because the speed of rotation of the cutting knives and the speed of passage of the corrugated board through the machine are substantially the same, the knives tend to cut or slit the board by a tearing or pressure rending action which at times causes the edges of the cut portions to be slightly ragged. In addition, due to its construction, one edge of the severed corrugated board is pressed out of shape so that the edge of the board is not parallel with the rest of the surface of the same. Moreover, the knives become dull very rapidly in use and require rather frequent sharpening. A further disadvantage of such machines is that the adjustment of the knives within the close limits desired is diflicult to effect.

The principal object of our invention is to provide an improved machine for cutting corrugated board wherein the knives for cutting or slitting the corrugated board are held stationary while the corrugated board is fed through the machine.

Another object of our invention is the provision of a machine for cutting corrugated board in which a unit of the corrugated board is fed through the machine and a plurality of incisions cut therein to form a plurality of unsevered sections of corrugated board capable of being readily folded through 180 degrees on the incision lines to lie facing one upon the other.

A further object of our invention is the provision of a machine adapted to form a plurality of incisions in a unit of corrugated board, the incisions being formed alternately on opposite sides of the corrugated board, enabling the unit to be folded into a protective corner or edge pad structure having a plurality of plies of corrugated board on either or both sides of the corner.

Another object of our invention is the provision of a machine for slitting corrugated board in which the knives or other means for performing the slitting operations are susceptible of fine and accurate adjustment.

A further object of our invention is to provide an improved construction of knife holder which is easily and quickly assembled or disassembled and easily adjustable in a machine of this type.

A further object of the invention is the provision of an improved multiple blade or knife holder capable of easy adjustment to selectively present knives for cutting various depths, or for presenting various blades or knives set for the same depth of cut so that when one dulls, another can replaced it by a simple adjustment of the holder.

A further object of the invention is to provide an imof cut desired.

Other objects and advantages will be more apparent from the following description wherein reference is had to the accompanying drawings, upon which Fig. 1 is a side elevational view of one type of slitting machine embodying the invention, a portion of the support table being broken away;

Fig. 2 is a fragmentary cross-sectional view thereof taken generally on the line 22 of Fig. 1;

Fig. 3 is a cross-sectional view through a sheet of corrugated board showing the manner in which it is slit from opposite faces of the same to form a protective pad;

Fig. 4 is a fragmentary perspective view showing a fragment of a pad formed in this manner;

Fig. 5 is a fragmentary vertical cross-sectional view through the machine taken generally on the line 5-5 of Fig. 2;

Fig. 6 is a side elevational view of a modified type of knife holder; and

Fig. 7 is a plan view thereof.

In the embodiment of the lIlVfiIltlOll which we have chosen to illustrate and describe, in Fig. l we have shown an end elevational view of one type of slitting machine 10 which may include the feed rolls 12 and 14 adjacent the edge of a horizontally disposed table 16 upon which the corrugated board B is positioned. The feed rolls 12 and 14 may be mounted at spaced intervals (see Fig. 2) and in alignment with the feed rolls 12 and 14 upon horizontal shaft members 18 and 20 disposed in bearings 22 and 24 at opposite ends of the machine.

Pull rollers 26 and 28 may be mounted at spaced intervals (see Fig. 2) and in alignment with the feed rolls 12 and 14 upon suitably horizontally disposed shafts 30 and 32 that are disposed in bearings 34 and 36 at each end of the machine 10. The brackets 40, one at each end of the machine for supporting the bearings mentioned, are mounted upon a channel member 42 which extends the length of the machine, the channel member being suitably fastened upon'leg members 44 and 46 to support the machine at the desired height.

Theupper bearings 22 and 34, together with an end bearing 48 for a knife mounting shaft 50, may be sup ported in vertical brackets 52 and 54 which have a cap 56 across the top of the same, the cap being provided with a tapped bore 58 for a screw member 60. The screw member 60, by means of hand wheels 62, one at each end of the machine, is adapted to raise the bearings 22, 34 and 48, depending upon the thickness of the corrugated board which is being slit. Ordinarily an A-flute, a B-flute or a double Wall comprises the three thicknesses which it is desired to slit. A lower knife blade mounting shaft 64 is mounted between the rollers 14 and 28 in a stationary bearing 66.

A drive for both the feed rollers and pull rollers may be obtained from any suitable source such as a motor by means of a shaft 68 which has a sprocket wheel 70 thereon. A similar sprocket 72 may be mounted upon shaft 20 and a sprocket 74 on shaft 18. A drive chain 76 may extend about the driven sprocket 70 and around the sprockets 74 and 72 and an idler sprocket 78 which is carried by a weighted arm 86 pivotally mounted on the end of the knife shaft 64 to take up the slack in the chain if there is an adjustment of the distance between the feed rolls 12 and 14. A pair of chain drives (not shown) connect the shafts 18 and 30 of the upper set of feed and pull rolls and the lower sets 14 and 28.

Referring now to Figs. 2 to 5 inclusive, the knifemounting shafts 50 and 64 each have a plurality of knife brackets 82 and 83 mounted thereon, the bracket 82 being generally U-shaped to encompass the square shaft 50 with a cover plate 84 fastened across the top of the same by means of the set screws 86. Each of the brackets 82 has a U-shaped slot 88 on the side thereof to receive 'a knife clamp90 which has a shoulder that fits within the slot and fastens a knife blade K in cutting position therein.

The lower knife supporting bracket 83 may also be U-shaped in form and is adapted to be placed in an inverted position over the knife shaft 64, being fastened thereto in a desired lateral position by means of a set screw 92 screw-threadedly mounted on one leg of the same, the set screw fastening against the side of the knife shaft 64.

It will be noted that the face 94 of each of the brackets 82 and 83 is on a comparatively large arc to provide a guide for directing the corrugated board B between the same. As previously pointed out, it is desirable to prevent the edge of the corrugated board from being pressed outof shape when it is desired to use a padding formed of a plurality of unsevered sections of corrugated board.

Thus, with the knife holders shown and as exemplified vin Figs. 2, 3 and 4, it can be seen that the corrugated board B is cut by the knife blades K without pressing any portion of the edge of the board out of shape, so that, as shown in Fig. 4, a padding P has been provided which has the parallel upper and lower walls 100. While in this illustration there are only four thicknesses of the corrugated board, it can be seen that with this method of cutting, the thickness can be increased as desired, and will always result in upper and lower edges 100 that are parallel.

In Figs. 6 and 7 We have shown a further modified form of knife holder which may comprise a bracket 118 that has a U-shaped socket 120 in the top of the same, the socket adapted to receive the mounting shaft 50. An

arm 122 may extend across the top of the legs of the U- shaped socket and fasten the knife holder on the mounting shaft by means of set screws 124. The knife holder may have an arm 126 adapted to extend forward so that the knife blade K may be positioned directly below the axis of feed rollers 12, the arm having a forward arcuate edge 128 to assist in guiding the board beneath the knife holder 118. As previously mentioned, the feed rolls 12 and 14 are spaced at desired intervals and in alignment with the pull rolls 26 and 28, and the knife holders are 'mounted on the shaft 50 between spaced pairs of feed rolls 12 and 14. The knife K is held in position by a blade clamp 130 which has a wedge portion 132 received in the U-slot 134 of the arm 126, the clamp being fastened to the knife holder by a pair of screw members 138. In a similar manner, the knife holder is inverted and fastened 4 v on shaft 64 to effect slitting on both surfaces of the corrugated board as hereinbefore explained and shown in the alternate form in Fig. 5.

From the above and foregoing description it can be seen that we have provided a corrugated board slitting machine which utilizes the principle of stationary knife blades positioned in the path of the unit of corrugated board, the blades being so arranged and held that they will slit the corrugated board without in any way pressing, tearing, or mutilating the edge of the board, leaving instead a sharp right angle edge upon both sides of the slot which has been formed, this being especially desirable for using a corrugated board in bending up padding, as shown in Figs. 3 and 4.

Due to the simplicity of the knife holders, the blades and their easy accessibility for interchange or sharpening, it can be seen that we have provided a highly efficient yet simple mechanism of the type described.

We contemplate that changes and modifications may be made in the exact details shown and We do not wish to be limited in any particular; rather what we desire to secure and protect by Letters Patent of the United States is:

1. A slitting machine having sets of feed and pull rolls with their axes parallel and the grip portions lying in a common plane and spaced apart in the direction of feed, one of said roll sets comprising two pairs of rolls axially spaced apart to provide a clear space therebetween im mediately adjacent the said plane, a slitting knife mounting shaft located in the space between the roll sets and parallel to the roll axes, a knife holder adjustably mounted on said shaft, said holder having an arm extending into said clear space between said two pairs of rolls, said arm having a knife afiixed thereto, the cutting edge of said knife located in said clear space to slit material, fed through the roll sets, substantially in the plane of the axes of the said two pairs of rolls.

2. The structure of claim 1, said knife holder arm having its free end portion arcuately shaped to guide the material between the rolls and past the knife.

References Cited in the file of this patent UNITED STATES PATENTS 1,234,884 Dozier et a1. July 31, 1917 1,356,271 Dozier Oct. 19, 1920 1,734,643 Olsen Nov. 5, 1929 2,120,920 Masters et al June 14, 1938 FOREIGN PATENTS 863,760 France Apr. 9, 1941 

